Footage showed the attackers punching and kicking a man while he was being taken away by police.

In recent months, there have been a spate of assaults and murders by cow vigilantes.

The police said the mob raided a privately-owned dairy farm in Aligarh, just an 4-hour drive from the national capital of Delhi, where they found five men skinning a buffalo, whose slaughter is legal at permitted abattoirs.

The dairy owner, Kalu Baghel, said the buffalo was sick and had stopped yielding milk, so he sold it to a cattle trader identified as Imran who said that in order for the transaction to go through, he must be permitted to slaughter the animal within the premises of the dairy farm.

Imran and five other men, all Hindus, were in the process of slaughtering the buffalo when the mob arrived.

Local police chief Rajesh Kumar Pandey said an investigation would determine how the buffalo died, and the skinners would be held for questioning.

"They have been arrested on charges of animal cruelty, and further charges will depend on the outcome of the autopsy report," he said.

None of the attackers - have been arrested as police had not received a formal complaint from the victims, he added.

The men arrested are Dalits, a caste that is often tasked with skinning dead cows, a major source of hides for the booming leatherwork industry.